class_docstr: Gather the dataset file from NAF dataset. Specifically for the case that
  there is a split file that contains the names of different splits. For
  example,
  
      img_001.jpg                           train: img_001.jpg
      img_002.jpg ---> split_file ---> test: img_002.jpg
      img_003.jpg                           val: img_003.jpg
  
  Args:
      split_file (str, optional): The name of the split file. Defaults to
          "data_split.json".
      temp_dir (str, optional): The directory of the temporary images.
          Defaults to "temp_images".
code: def __init__(
      self,
      split_file="data_split.json",
      temp_dir: str = "temp_images",
      **kwargs,
  ) -> None:
      super().__init__(**kwargs)
      self.temp_dir = temp_dir
      self.split_file = split_file
  
file_path: mmocr/mmocr/datasets/preparers/gatherers/naf_gatherer.py
imports: import json
  import os
  import os.path
  import shutil
  from typing import List, Tuple
  from mmocr.registry import DATA_GATHERERS
  from .base import BaseGatherer
label_desc: Use image node_id 1 to create a new NAFGatherer object from inherited base classes: BaseGatherer with example: obj = NAFGatherer(split_file, temp_dir)